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Erroneous Proof of Work calculation in geth

Moderate severity GitHub Reviewed Published Nov 24, 2020 in ethereum/go-ethereum • Updated Jan 30, 2025

Package

gomod github.com/ethereum/go-ethereum (Go)

Affected versions

< 1.9.24

Patched versions

1.9.24

Description

Impact

An ethash mining DAG generation flaw in Geth could cause miners to erroneously calculate PoW in an upcoming epoch (estimated early January, 2021). This happened on the ETC chain on 2020-11-06. This issue is relevant only for miners, non-mining nodes are unaffected.

Patches

This issue is also fixed as of 1.9.24. Thanks to @slavikus for bringing the issue to our attention and writing the fix.

Workarounds

This PR implements a patch: ethereum/go-ethereum#21793

References

https://blog.ethereum.org/2020/11/12/geth_security_release/

For more information

If you have any questions or comments about this advisory:

References

@holiman holiman published to ethereum/go-ethereum Nov 24, 2020
Reviewed May 21, 2021
Published to the GitHub Advisory Database Jun 29, 2021
Last updated Jan 30, 2025

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
Required
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(51st percentile)

Weaknesses

CVE ID

CVE-2020-26240

GHSA ID

GHSA-v592-xf75-856p

Source code

Credits

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